Point-of-care testing of activated clotting time in the ICU: is it relevant?

Viscoelastic Testing in the Management of Adult Patients on Mechanical Circulatory Support Devices with Focus on Extracorporeal Membrane Oxygenation

Thromboembolic and hemorrhagic complications continue to remain frequent complications that significantly impact the morbidity and mortality of patients implanted with mechanical circulatory support devices (MCSDs). The severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) has resulted in a number of COVID-19 patients being supported by MCSDs, specifically extracorporeal membrane oxygenation (ECMO), which in turn has created a crucial need for rapid assessment of hemostatic status in these patients to avoid bleeding and thrombotic complications. Currently, conventional plasma-based coagulation assays such as prothrombin time and activated partial thromboplastin time (aPTT) are used to assess hemostasis, and the activated clotting time (ACT) and aPTT are the most common tests used to monitor heparin anticoagulation in patients on ECMO. Unfractionated heparin remains the mainstay anticoagulation therapy for patients on ECMO. Extracorporeal Life Support Organization (ELSO) offers little guidance on the subject but does state that each institution should create its internal anticoagulation protocols. Viscoelastic assays (VEAs) are increasingly recognized by ELSO and ECMO community for their potential to assess hemostatic derangements in patients implanted with MCSDs as well as guidance for appropriate hemostatic therapy. This review focuses on the evidence for the use of viscoelastic assays to assess overall hemostasis and to guide the treatment of adult patients connected to an ECMO circuit. Limitations of the use of conventional assays, ACT, and VEA are also discussed.

Benefits and Pitfalls of Point-of-Care Coagulation Testing for Anticoagulation Management: An ACLPS Critical Review

Objectives

Point-of-care (POC) testing is generally less precise and has higher reagent costs per test than laboratory-based assays. However, POC hemostasis testing can offer significant advantages in particular situations: patient-managed warfarin therapy as well as rapid turnaround time heparin management for intraoperative patients. Of note, POC hemostasis testing is generally approved for the purposes of anticoagulation monitoring and is inferior to laboratory coagulation testing for the diagnosis of congenital or acquired coagulopathy.

Methods

The frequently used POC coagulation instruments for POC international normalized ratio and activated clotting time are reviewed, as well as their typical performance relative to central laboratory testing (where available).

Results

Several cases are discussed that highlight the benefits, as well as pitfalls, of POC coagulation testing.

Conclusions

POC coagulation testing for anticoagulation monitoring offers advantages in particular situations. Clear policies and protocols must be developed to guide proper use of POC versus central laboratory hemostasis testing.